Everyone wants to live in a safe city. In the wake of terrorist attacks such as the one on the Berlin Christmas market in December and at the Istanbul nightclub on New Year’s Eve, that desire feels more urgent than ever. For places facing the threat of terrorism it’s essential to install measures to prevent such attacks and keep people safe – but strategies differ.

Some cities rely on hi-tech blanket surveillance, while others have fallen back on a strong and smartly trained police force. Others, such as London, have embedded security directly into the city itself, working with the built environment and street furniture to protect against attacks such as that in Berlin. Most are continually experimenting with new lines of defence against the changing threat of terrorism.

City-dwellers appreciate wise security measures – if they’re effective – but we must ensure that we aren’t disregarding our own freedoms and quality of life. There is a fine line between protection and privacy infringement; the presence of officers should be reassuring rather than stifling. As Ben Wizner of the American Civil Liberties Union puts it: “We wouldn’t want to live in a society that used every power at its disposal to prevent every possible attack because that would mean we lived in a police state.”

The city of Monterrey in Mexico’s northeast state of Nuevo León is one of the nation’s wealthiest. An industrial metropolis, it is home to more than one million residents and many of Mexico’s most successful companies.

Until recently it was also a relatively safe place to live; the state recorded fewer than 200 murders a year between 1990 and 2006. In 2007, however, violent crime in Monterrey and the surrounding area began to increase as drug-trafficking organisations began running incursions into the city, engaging in shootouts in densely populated areas and targeting businessmen for kidnapping and extortion.

In 2011 an astounding 2,174 murders were recorded. The terrifying new generation of military-style drug cartels, who used high-powered weapons and travelled in armoured caravans, were able to overpower and outgun police units. Cartel gunmen carried out co-ordinated attacks, shut down transport routes, detonated a remote-controlled car bomb and set a casino ablaze, killing 52 people.

And so an entirely new police force was born: the Fuerza Civil, highly trained and carefully selected to prevent corruption. Partially funded by the private sector – business owners realised the value in increasing security – the Fuerza Civil started patrols in September 2011. Officers were given tactical training in order to learn how to effectively confront groups of armed gunmen and a new intelligence centre was built in order to co-ordinate with field agents to detect and pursue criminal groups.

The officers were recruited from outside the ranks of existing police to allow the force to start from scratch. Salaries were doubled, residential facilities for officers were built and strict procedures established to prevent corruption. “The Fuerza Civil is good,” says Miguel Treviño, a security analyst at Monterrey consultancy RiskOp. “The government is working to combat corruption.”

The new police force has been well received. “Shootouts, bodies hung from bridges – that’s all less common now,” says Treviño. By 2015, murders across the state fell to about a fifth of their 2011 levels and business in Monterrey is once again flourishing.

Monocle comment: An incorruptible police force is essential. But officials should be cautious about introducing special forces without due cause, lest they become a militarised police that even non-criminals fear more than they trust.

Israelis have long viewed Ramat Hasharon as a quality-of-life destination. But such is the national obsession with security that the city of 45,000 has opted to become one of Israel’s pioneer “safe cities”, protected by an extensive surveillance network that allows officials to respond rapidly to crime, catastrophe and terror threats. The ils9m (€2.2m) system is being rolled out by Israeli security company Magal S3, best known for constructing the perimeter fence that keeps about 1.8 million Palestinians in Gaza.

In Ramat Hasharon, however, the company has been asked to take a more discreet approach. “No one wants fences around their city,” says Yaniv Shachar, chief operations officer of Magal Israel.

Instead video technology is key here. Along with motion sensors, more than 200 security cameras are spread throughout the city, with a fibre-optic communications system ensuring the speedy transfer of data to a dedicated control centre. Panic buttons have been installed inside vulnerable locations such as nurseries and all security-related computer systems are backed up, with an emergency network ready in reserve.

Wraparound security is a service that a wealthy municipality such as Ramat Hasharon can deliver to its residents, who seemingly have fewer reservations about the implications of mass surveillance than their counterparts in other parts of the developed world. Though it’s an extreme approach to security it’s not without demand. The scheme’s popularity has been such that Magal has started to implement the same project in Holon, a coastal city south of Tel Aviv. Further afield there has been interest from Nigeria, China and India.

Monocle comment: Though many cities rely on cctv, we should be cautious about embracing wide-scale systems. In the age of NSA monitoring and data collection, the line between monitoring systems and full-blown surveillance is blurry.

London’s preparedness for a terror attack was recently paid an unsavoury but unarguably well-informed compliment. Mohamed Abrini, the Moroccan-Belgian accused of organising attacks in Paris in 2015 and Brussels in 2016, told police that the UK “has a more developed secret service, better observation techniques and is therefore more difficult to attack”.

In October 2016 it was revealed that UK security and counter-terrorism units had foiled at least 10 attacks in the previous two years. Yet London’s history with terrorism attacks – from Guy Fawkes and the ira to the 7/7 bombings – is a warning against complacency.

The difficulty of the terror threat is that it doesn’t disappear: it merely mutates, adapting to preventative measures. There are other difficulties unique to cities such as London. Last year Lord Harris of Haringey, who sits on the UK parliament’s Joint Committee on the National Security Strategy, delivered a review commissioned by London mayor Sadiq Khan into London’s capacity to respond to a major incident. While generally positive, it noted that 54 per cent of the city’s paramedics, police and fire-fighters live outside the city, which could cause difficulty if swift recall was required.

Yet there is a fine balance between a robust security presence and maintaining the atmosphere of an open city, one that London has not always got right. In 2003 barriers were placed outside the Houses of Parliament, prompting criticism of their physical and political ugliness.

“Ultimately it’s a political judgement,” says Lord Harris. “An armed unit on every corner would change the look and feel of the city – and that’s something that people have to think carefully about.”

The thinking has since become more subtle. In 2007 the UK established the Centre for the Protection of National Infrastructure (cpni), accountable to mi5, with a remit to reduce the vulnerability of key assets, often by disguising security measures as city furniture. These measures can prevent attacks such as the one that took place in Berlin in December.

“Look at Whitehall,” says former senior police officer Chris Phillips, whose consultancy Ippso has worked with the cpni. “In the past 10 years walls have been built close to the road that look like they’ve been there forever. They are actually hostile-vehicle mitigation to prevent people crashing into government buildings.”

Such measures can become features. Phillips notes that the concourse around the Tower of London has been pedestrianised with the addition of barely noticeable vehicle blockers, while city hall and many other prominent buildings are surrounded by concrete benches that are as likely to entice picnickers as deter vehicle-bombers. In addition to protecting London, says Phillips, they “have actually made it a nicer environment”.

Monocle comment: Embedding security features into street furniture can provide protection without appearing unwelcoming to those who call it home.